Device for vacuum packaging, particularly of food products

ABSTRACT

A packaging device, particularly for packaging trays containing food products or technical materials in a controlled atmosphere and by means of a film of plastic material, comprising an upper chamber and a lower chamber, which can be fastened by mutually superimposing them and are each provided internally with a plurality of heat-sealing and/or cutting and/or die-cutting elements arranged concentrically, the lower chamber being provided centrally with a plurality of supporting elements for a tray.

TECHNICAL FIELD

The present invention relates to a packaging device, particularly forfood products or technical materials.

BACKGROUND ART

Vacuum machines are currently known which have a bell-shaped chamber andcomprise a vacuum pump which is connected to a chamber, also known asvacuum chamber, inside which there is usually a preformed pouch, whichis open on three sides and inside which a food product is placed.

In these machines of the known type, the preformed pouch, with theproduct already inside, is then inserted in the vacuum chamber and thenvacuum is produced inside the chamber; a heat seal is then provided atthe free side of the preformed pouch.

This known technology entails the need to use preformed pouches whichtherefore have a size that can be compared to that of the product.Moreover, considerable labor is required.

Operating steps therefore occur which increase the time required toachieve vacuum packaging of the product. Furthermore, if packagingoccurs in a controlled atmosphere, a large proportion of the gas iswasted, since the gas is dispersed not only into the pouch but mostlyalso inside the vacuum chamber.

EP603704 is also known in which food products are packaged by using afilm of plastic material which is guided through a folding station inorder to obtain a double layer and is then heat-sealed so as to definepouches.

These pouches are obtained in the desired size or capacity before beingfilled and sealed.

Heat-sealing and forming are followed by filling, as well as by theclosing and cutting of the pockets or pouches thus obtained. However,this solution is complicated, in that it has multiple and distinctstations for performing the individual operations to which the film ofplastic material must be subjected in sequence.

Furthermore, hot or cold forming of the plastic film is provided, and sois the filling, by means of a nozzle, with liquid products, flours orfinely granulated products, and therefore it is not possible to considerthe use of the described solution for solid products having presetvolumes, such as sliced ham and salami, meat, cheese in portions, trayscontaining food and nonfood products.

Moreover, in the described known solution, in order to achieve closureof the pocket or pouch it is necessary to pass it through various stepsof operation, with the consequent need for optimum centering of thepouch at each station so as to allow optimum and desired processing.

EPA0405718 is also known which illustrates a solution for a packagingdevice, particularly for packaging food products or technical materialsthat can be inserted between longitudinally folded parts of asingle-folded film from one of its open sides. The device comprisesthermal bonding means or heat-sealing means which are substantiallyL-shaped so as to seal the film both at the open longitudinal side andat its transverse sides, and at least one nozzle for generating vacuumand/or for introducing the gas or mixture.

EP0832819B1 is also known which has, as its priority, Italianapplication AL960002 dated 26 Sep. 1996, which describes a packagingdevice which comprises a vacuum chamber which can be opened to receive alength of at least one single-folded film with the material to bepackaged inserted therein, and respectively can be closed hermetically,after which it is possible to produce vacuum and/or introduce the gas ormixture with the portion or length of film assuming a pocket-likeconfiguration, heat-sealing means being furthermore provided which arearranged for operation within the vacuum chamber, the at least onenozzle being arranged at the vacuum chamber so as to be directed, afterits closure, toward the open longitudinal and/or transverse sides of thelength of film.

This solution, too, is not free from drawbacks, since the forming ofmicro-creases has been observed during the heat-sealing of the film, andthis can entail problems in tightness and worsens the aestheticappearance of the package.

Furthermore, the flow of the gas inside the film is not optimum,reducing the efficiency of the device.

Finally, when the operator pulls the sheet, the sheet can assume anincorrect arrangement.

Another problem is also noted: when vacuum is provided in a bell, andaccordingly in the pouch being formed, it is then necessary tocompensate the vacuum partially with the gas; however, if thecompensation is excessive, the bell opens during heat-sealing.

Since one works with a system in a particularly variable equilibrium,there is no precise control over the volume of gas introduced in the bagor pouch being formed.

The quantity, both in absolute terms and in relative terms (%), of gasthat remains inside the pouch being formed is therefore extremelyvariable and difficult to control, and this leads to the provision of aseries of pouches or packages which are more or less inflated ordeflated depending on the situation.

The problem is then worsened if it is necessary to change package formatoften.

Another problem is observed in the step of heat-sealing of the film,which is heat-sealed and cut on the transverse side with respect to thedirection of advancement of the film: since it is often made ofheat-shrinking material, the film can retract, reducing its width, andthis might prevent the accommodation of the oncoming tray.

The tray can thus arrive and find a space that is insufficient toaccommodate it, and this causes its diversion toward the open side ofthe pouch, ending on the longitudinal heat-sealing bar, causing machinedowntimes and waste of time for cleaning the machine.

Finally, it is noted that the return of the air into the bell or vacuumchamber occurs, due to constructive reasons, usually in a region that isfar from the heat-sealing bar or coincides with the vacuum hole by meansof the use of a three-way valve, but this does not optimize theconveyance of the flow inside the bell.

Heat-sealing machines for preformed trays are also known. In order touse heat-sealing machines, and therefore when it is necessary to changethe size of the package to be sealed and then trim the film heat-sealedonto the edge of the tray with a die cutter, the user must intervene bychanging at least one mechanical part, commonly known as die.

Such die is constituted by a hot upper element, which is shaped like thetray to be packaged, by a die-cutter, which will follow the edge of thetray in order to cut the film, and by a lower element, which constitutesthe receptacle of the tray for heat-sealing and cutting.

The problem that is observed is constituted by the considerable timerequired to change the die as a function of the shape of the tray to beheat-sealed.

Machines are also known which, in order to give greater flexibility tothe system, provide, once the machine has stopped, an automatic changingof the upper element of the die. Such upper element is provided with twoor more (up to four) dies which have two or more vacuum chambers whichrotate on a horizontal axis.

In this manner, the operator, in order to change the die, must, afterstopping the machine, select which die he or she will use and the diewill be preheated.

Once the desired temperature has been reached, it is necessary to rotatethe upper element, bringing it at the work region, and replacephysically the lower element (which must match up exactly with the upperone) in order to be then able to begin work with the new format.

This solution is mechanically very complicated and expensive, and italso has processing downtimes that affect the overall costs of themachine.

DISCLOSURE OF THE INVENTION

The aim of the present invention is therefore to solve the abovementioned technical problems, eliminating the drawbacks of the citedbackground art, by providing a device that makes it possible to achievevacuum packaging or compensated vacuum or only the sealing of technicalproducts or food products such as sliced ham and salami, meat, cheese inportions, placed in trays of the desired size, rapidly and simply.

Within this aim, an object of the present solution is to provide adevice that makes it possible to achieve vacuum packaging or compensatedvacuum or only the sealing of products placed in trays of the desiredsize in short times and without any need for machine stops.

Another object is to provide a device that is structurally simple andcan be used even by an operator who is not particularly trained.

Another object is to provide a device that allows optimum heat-sealingof the tray, avoiding machine stops and waste of time for cleaning saidmachine and replacing the die.

This aim and these objects, as well as others which will become betterapparent hereinafter, are achieved by a packaging device, particularlyfor packaging trays containing food products or technical materials in acontrolled atmosphere and by means of a film of plastic material,characterized in that it comprises an upper chamber and a lower chamber,adapted to define a chamber for accommodating a tray, which can befastened by mutually superimposing them and are each provided internallywith a plurality of heat-sealing and/or cutting and/or die-cutting meansarranged concentrically, said lower chamber being provided centrallywith a plurality of supporting means for said tray.

BRIEF DESCRIPTION OF DRAWINGS

Further characteristics and advantages of the present invention willbecome better apparent from the detailed description of two particularembodiments, illustrated by way of non-limiting example in theaccompanying drawings, wherein:

FIG. 1 is a partially sectional lateral perspective view of the devicewithout the supporting roller for the film;

FIG. 2 is a first side view of the device;

FIG. 3 is a sectional view, taken along the line III-III of FIG. 2;

FIG. 4 is a top view of the device;

FIG. 5 is a second side view of the device;

FIGS. 6 to 10 are sectional views of the operation of the device;

FIG. 11 is a view of the device in a detail shown in FIG. 8.

WAYS OF CARRYING OUT THE INVENTION

In the exemplary embodiments that follow, individual characteristics,given in relation to specific examples, may actually be interchangedwith other different characteristics that exist in other exemplaryembodiments.

With reference to the figures, the reference numeral 1 designates adevice for the packaging particularly of technical materials or foodproducts placed within an adapted tray 2.

The device 1 comprises an upper chamber 3 and a lower chamber 4 whichare shaped like a vacuum bell, each being constituted essentially by acontainer that can be fastened onto the other one hermetically bysuperimposing.

Known means, not shown, are also present which are suitable to obtain,within the upper chamber 3 and the lower chamber 4, a controlledatmosphere or a vacuum.

Adapted bands or gaskets for airtightness, not shown, are providedperimetrically to the lateral edge 5 a, 5 b of the upper chamber 3 andof the lower chamber 4.

The device preferably uses a film 6 made of plastic material, which isunwound from an adapted roll 7 which is associated in an upper regionand at one side of the upper chamber 3 and then guided on adapted pairsof guiding elements 8 a, 8 b which are present proximate to the lateraledges 5 a, 5 b of the upper chamber 3 and of the lower chamber 4.

The film 6 is then rewound onto a winder which is operated by an adaptedfirst motor 10 which is arranged laterally to the upper chamber 3.

Heat-sealing and/or cutting and/or die-cutting means are provided insideeach one of the upper chamber 3 and of the lower chamber 4 and arearranged concentrically within the chambers so as to define internallyand centrally a free space 11 onto which the tray 2 is to be made toact.

The heat-sealing and/or cutting and/or die-cutting means are composed ofa series of upper pressers 12 a, 12 b, 12 c, which are inserted in eachother, are arranged mutually coaxially within the upper chamber 3 andare provided with heat-sealing and/or cutting and/or die-cuttingsystems.

In the particular embodiment, the upper pressers are three in number,but their number might vary according to specific requirements.

The heat-sealing and/or cutting and/or die-cutting means also comprise aseries of lower pressers 13 a, 13 b, 13 c, which are arranged so as tobe inserted in each other coaxially within the lower chamber 4 and arearranged, with respect to the upper pressers 12 a, 12 b, 12 c, so as tocorrespond respectively to the upper pressers.

The upper pressers 12 a, 12 b, 12 c and the lower pressers 13 a, 13 b,13 c can thus move vertically because they are actuated by adaptedactuators 14 such as pneumatic cylinders which are arranged preferablyabove the upper chamber 3 and below the lower chamber 4.

As an alternative, only the upper pressers 12 a, 12 b, 12 c or only thelower pressers 13 a, 13 b, 13 c can be movable.

In the particular embodiment shown, the upper pressers 12 a, 12 b, 12 care box-shaped, with a height that corresponds to a particular tray 2 tobe heat-sealed. The lower pressers 13 a, 13 b, 13 c are insteadconstituted by concentric rings of the same height, whose function is toabut against the perimetric edges 15 of the corresponding and overlyingupper pressers 12 a, 12 b, 12 c.

The lower pressers 13 a, 13 b, 13 c are further provided, at the lateraledges that are adjacent to the end that faces the upper pressers 12 a,12 b, 12 c, with blades 19 which are adapted to allow the cutting of thefilm 6 during the work cycle, as shown in FIG. 11.

At the free space 11 a plane 16 is provided, which can move verticallywith respect to the lower chamber 4 by means of an adapted shaft 17which can slide with respect to the footing 18 of the lower chamber 4.

The support for the tray 2 can be advantageously of the spring-loadedtype.

Use of the invention is as follows.

The arrangement of the upper pressers 12 a, 12 b, 12 c and of the lowerpressers 13 a, 13 b, 13 c, so that the former are concentrical to thelatter or at least the former are contained in the latter, enables topredefine the type of tray to be used, achieving the heat-sealing andcutting of the film 6 rapidly and simply.

Beforehand, the operator does not have to select in any way which trayhe or she wishes to package, but simply rests the tray of the desiredsize in an adapted loading area, centering it with respect to theloading plane 16 of the device 1.

As an alternative, it is possible to provide an automatic means for thecentering of the tray 2 before sending it to the device 1.

At this point the tray can be inserted, manually or by means of anadapted fixed-stroke pusher, in its position inside the device 1 andthus be positioned on the plane 16, as shown in FIG. 3.

The loading system brings it, by means of a movement unit, to asizing/centering system. Once the system has recognized the size of thetray, the tray is placed automatically, by way of a movement system, atthe center of its lower loading region and at the same time the filmperforms an advancement which is suitable for the type of tray to beheat-sealed.

At this point the upper chamber 3 and the lower chamber 4 close, thelatter rising (see FIG. 6), and at the same time the desired one amongthe upper pressers 12 a, 12 b, 12 c (see FIG. 7 for the upper presser 12c) and the corresponding one among the lower pressers 13 a, 13 b, 13 c)(see FIG. 8) are moved vertically.

The vacuum or gas vacuum cycle, for example, can thus start, and at itsend the heat-sealing and cutting step begins, performed by utilizing theupper and lower pressers (see for example FIG. 8, in which the blade 19of the lower presser 13 c has risen and cuts the film 6 along the edgeof the tray 2), or by means of a mechanical system or a system ofanother known type, which applies pressure onto an adapted heat-sealingblock which corresponds to the tray and heat-seals and cuts the filmonto the tray.

Once this step has ended, the vacuum chamber opens (see FIG. 9, in whichthe upper presser 12 c has also risen and the lower chamber 4 hasdescended) and the lower pressers 13 a, 13 b, 13 c descend and the plane16 rises until the tray 2 that has just been sealed is brought to theunloading level in order to proceed with a new process (see FIG. 10).

As has been shown, the practicality of use of being able to load thetray in the desired format at each cycle has been achieved, the traybeing heat-sealed and die-cut without the need for any intervention onthe part of the operator.

The device 1 obviously comprises, for heat-sealing and cutting, meansadapted to activate the upper pressers 12 a, 12 b, 12 c and the lowerpressers 13 a, 13 b, 13 c depending on the size of the tray 2 of thechosen size.

FIGS. 3, 6, 7, 8, 9 and 10 illustrate the operation of the device.

It has thus been found that the invention has achieved the intended aimand objects, a device having been obtained which makes it possible toachieve vacuum packaging or compensated vacuum or only the heat-sealingof technical products or food products such as sliced ham and salami,meat, cheese in portions, placed in trays of the desired size, rapidlyand simply without the need for any machine stops.

Moreover, the device is structurally simple and can be used even by anoperator who is not particularly trained.

The invention is of course susceptible of numerous modifications andvariations, all of which are within the scope of the appended claims.

Thus, for example, it is also possible to load two trays simultaneouslyand double the production.

Alternatively, it is possible to have a die-cutter system which isanchored to the upper chamber 3 or to the lower chamber 4 or a systemfor centering the part by means of mechanical or electrochemicalpositioning units.

The shape and number of the upper pressers 12 a, 12 b, 12 c and of thelower pressers 13 a, 13 b, 13 c of course may be the most disparateaccording to the specific requirements.

Conveniently, it is possible to provide for the presence not only of theabove mentioned centering means, but also of means for recognizing thetype of tray, adapted to recognize the tray on the basis of itsdimensions or of a code that is present on the tray itself.

Advantageously, the recognition means can comprise a vision system.

As a further alternative, it is possible to provide, at the upperchamber, a plurality of heat-sealing and/or cutting and/or die-cuttingmeans, in a manner similar to what has been described above, but withthe difference that such heat-sealing and/or cutting and/or die-cuttingmeans are fixed.

Therefore, differently from the first embodiment, the heat-sealingand/or cutting and/or die-cutting occurs exclusively by moving the lowerchamber toward the upper chamber, without actuating for lowering theindividual heat-sealing and/or cutting and/or die-cutting means of theupper chamber.

Essentially, in this second embodiment there are no presser means at theupper chamber.

The film used can be both of the single-folded type and of the flatsheet type.

The materials used, as well as the dimensions that constitute theindividual components of the invention, may of course be more pertinentaccording to specific requirements.

The various means for performing certain different functions need notcertainly coexist only in the illustrated embodiment, but can be presentper se in many embodiments, including ones that are not illustrated.

The characteristics indicated as advantageous, convenient or the likemay also be omitted or be replaced with equivalents.

The disclosures in Italian Patent Application no. TV2010A000164, fromwhich this application claims priority, are incorporated herein byreference.

Where technical features mentioned in any claim are followed byreference signs, those reference signs have been included for the solepurpose of increasing the intelligibility of the claims and accordinglysuch reference signs do not have any limiting effect on theinterpretation of each element identified by way of example by suchreference signs.

1-14. (canceled)
 15. A packaging device, particularly for packagingtrays containing food products or technical materials in a controlledatmosphere and by means of a film of plastic material, comprising anupper chamber and a lower chamber, adapted to define a chamber foraccommodating a tray, which can be fastened by mutually superimposingthem and are each provided internally with a plurality of heat-sealingand/or cutting and/or die-cutting means arranged concentrically, saidlower chamber being provided centrally with supporting means for saidtray.
 16. The device according to claim 15, wherein said film is asingle-folded film, said upper chamber and said lower chamber beingconstituted by a container which can be fastened onto the othercontainer hermetically by superimposition, bands or gaskets forairtightness being provided perimetrically to the lateral edge of saidupper chamber and of said lower chamber.
 17. The device according toclaim 16, wherein said film of plastic material is unwound from a roll,which is associated in an upper region and at one side of said upperchamber and then guided on pairs of guides which are present proximateto said lateral edges of said upper chamber and of said lower chamber,said film being then rewound on a winder which is controlled by a firstmotor arranged laterally to said upper chamber.
 18. The device accordingto claim 15, wherein heat-sealing and/or cutting and/or die-cuttingmeans are arranged inside each one of said upper chamber and said lowerchamber and are arranged concentrically within said chambers so as todefine internally and centrally a free space on which said tray is to bemade to act.
 19. The device according to claim 18, wherein saidheat-sealing and/or cutting and/or die-cutting means are composed of aseries of upper pressers, which are inserted in each other and arrangedmutually coaxially within said upper chamber and are provided withheat-sealing and/or cutting and/or die-cutting systems.
 20. The deviceaccording to claim 19, wherein said upper pressers are three in number.21. The device according to claim 19, wherein said heat-sealing and/orcutting and/or die-cutting means comprise a series of lower pressers,which are inserted in each other and coaxially within the lower chamberand are arranged, with respect to said upper pressers, so as tocorrespond respectively to said upper pressers.
 22. The device accordingto claim 21, wherein said upper pressers and said lower pressers are,individually or together or alternately, movable vertically andcontrolled by actuators, such as pneumatic cylinders, which are arrangedpreferably above said upper chamber and below said lower chamber. 23.The device according to claim 19, wherein said upper pressers of saidupper chamber are fixed.
 24. The device according to claim 21, whereinsaid upper pressers are box-shaped, with a height that corresponds to aparticular tray to be heat-sealed, said lower pressers being constitutedby concentric rings of equal height, whose function is to abut againstperimetric edges of the corresponding and overlying upper pressers, saidlower pressers being provided, at the lateral edges that are adjacent tothe end that faces said upper pressers, with blades which are adapted toallow the cutting of said film during the work cycle.
 25. The deviceaccording to claim 24, wherein at said free space a plane is provided,which can move vertically with respect to said lower chamber by means ofa shaft, which can slide with respect to a footing of said lowerchamber, a support for said tray being of the spring-loaded type. 26.The device according to claim 15, wherein said film is of the flat sheettype.
 27. A packaging method, particularly for packaging trayscontaining food products or technical materials in a controlledatmosphere and by means of a film of plastic material, using a deviceaccording to claim 15, comprising the steps of: positioning, bycentering it, a tray at a support which is arranged at said lowerchamber, in a position below said upper chamber; moving for closure saidlower chamber toward said upper chamber or vice versa, actuating upperand/or lower presser means selected to correspond to the dimensions ofsaid tray.
 28. The method according to claim 27, further comprising thestep of determining automatically the size of said tray prior to theactuation of said presser means.